High field fractional quantum Hall effect in optical lattices

We consider interacting bosonic atoms in an optical lattice subject to a large simulated magnetic field. We develop a model similar to a bilayer fractional quantum Hall system valid near simple rational numbers of magnetic flux quanta per lattice cell. Then we calculate its ground state, magnetic lengths, fractional fillings, and find unexpected sign changes in the Hall current. Finally we study methods for detecting these novel features via shot noise and Hall current measurements.Comment: 4 pages, 4 figures, accepted by PR

A simultaneous spin/eject mechanism for aerospace payloads

A simultaneous spin/eject mechanism was developed for aerospace applications requiring a compact, passive device which would accommodate payload support and controlled-release functions, and which would provide a highly accurate spin-ejection motion to the payload. The mechanism satisfied the requirements and is adaptable to other deployment applications

EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes.

Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness

Searching for the most powerful thermonuclear X-ray bursts with the Neil Gehrels Swift Observatory

We searched for thermonuclear X-ray bursts from Galactic neutron stars in all event mode data of the Neil Gehrels Swift Observatory collected until March 31, 2018. In particular, we are interested in the intermediate-duration bursts (shell flashes fueled by thick helium piles) with the ill-understood phenomenon of strong flux fluctuations. Nine such bursts have been discussed in the literature to date. Swift is particularly suitable for finding additional examples. We find and list a total of 134 X-ray bursts; 44 are detected with BAT only, 41 with XRT only, and 49 with both. Twenty-eight bursts involve automatic slews. We find 12 intermediate-duration bursts, all detected in observations involving automatic slews. Five show remarkably long Eddington-limited phases in excess of 200 s. Five show fluctuations during the decay phase; four of which are first discussed in the present study. We discuss the general properties of the fluctuations, considering also 7 literature cases. In general two types of fluctuations are observed: fast ones, with a typical timescale of 1 s and up and downward fluctuations of up to 70%, and slow ones, with a typical timescale of 1 min and only downward fluctuations of up to 90%. The latter look like partial eclipses because the burst decay remains visible in the residual emission. We revisit the interpretation of this phenomenon in the context of the new data set and find that it has not changed fundamentally despite the expanded data set. It is thought to be due to a disturbance of the accretion disk by outflowing matter and photons, causing obscuration and reflection due to Thompson scattering in an orbiting highly ionized cloud or structure above or below the disk. We discuss in detail the most pronounced burster SAX J1712.6-3739. One of the bursts from this source is unusual in that it lasts longer than 5600 s, but does not appear to be a superburst.Comment: Accepted for publication in Astronomy & Astrophysics, 29 pages, 12 figures. Version 2 has 3 bursts from IGR J17480-2446 re-identified to 2 from Swift J174805.3-244637 and 1 from EXO 1745-24

Development and structure of karstification of the Dong Van Karst Plateau UNESCO Global Geopark, North Vietnam based on cave survey data

This paper presents a quantitative study of the relationship between the cave system and the tectonic and karst evolution of the Dong Van Karst Plateau based on analysis and statistics of geometric parameters and orientation of cave passages. The region is located in northern Vietnam and belongs to the extended part of the South China karst belt (Yunnan karst plateau), which is composed mainly of carbonate rocks. Cave classification based on cave conduits geometric parameters shows that caves developed mainly in the vadose zone (27 vadose branchwork caves, 10 mixed caves developed under the control of fault systems, and 12 water-table caves). The degree of correlation between cave levels and planation surfaces suggests that the development of horizontal cave passages is related to two levels of planation surfaces, including one at 1250–1450 masl (equivalent to cave level at 1350–1450 masl), and at 1000–1250 masl (corresponding to cave level at 1200–1250 masl). Additionally, cave passage orientation shows that the cave system formed and developed under the influence of tectonic activities in the Cenozoic. The dominant orientation trend is roughly in the East–West direction and occurred in the early phase (Eocene–Miocene). Next is a trend roughly North–South that occurred in the late phase (Pliocene–Quaternary). The last orientation trend follows the NW–SE direction due to the reactivation of paleo-fault systems in the same direction. Although there are limitations due to accessibility and the level of cave exploration, this research suggests that analysis and statistics of the geometric parameters and orientation of cave passages based on cave survey data can be one of the effective approaches used to identify the development and structure of karstification in the karst region

Disability Identification Cards: Issues in Effective Design

Around the world, the issue of disability inclusion is gaining increasing prominence. To promote disability-inclusion in programmes, a growing number of countries are considering the creation of a disability identification card. However, the administration of a disability ID card in low and middle-income countries differs from those in high-income countries. The purpose of this article is to discuss some of the challenges involved in creating a disability ID and how to address these challenges in the context of low and middle-income countries, suggesting that countries considering instituting disability ID cards must move with caution. ID card programmes can only advance disability policy and the wellbeing of persons with disabilities if undertaken in a well-designed manner in line with a country’s administrative capacity

The 100-month Swift catalogue of supergiant fast X-ray transients I. BAT on-board and transient monitor flares

We investigate the characteristics of bright flares for a sample of supergiant fast X-ray transients and their relation to the orbital phase. We have retrieved all Swift/BAT Transient Monitor light curves, and collected all detections in excess of $5\sigma$ from both daily- and orbital-averaged light curves in the time range of 2005-Feb-12 to 2013-May-31. We also considered all on-board detections as recorded in the same time span and selected those within 4 arcmin of each source in our sample and in excess of $5\sigma$. We present a catalogue of over a thousand BAT flares from 11 SFXTs, down to 15-150keV fluxes of $\sim6\times10^{-10}$ erg cm$^{-2}$ s$^{-1}$ (daily timescale) and $\sim1.5\times10^{-9}$ erg cm$^{-2}$ s$^{-1}$ (orbital timescale, averaging $\sim800$s) and spanning 100 months. The great majority of these flares are unpublished. This population is characterized by short (a few hundred seconds) and relatively bright (in excess of 100mCrab, 15-50keV) events. In the hard X-ray, these flares last in general much less than a day. Clustering of hard X-ray flares can be used to indirectly measure the length of an outburst, even when the low-level emission is not detected. We construct the distributions of flares, of their significance (in terms of sigma) and their flux as a function of orbital phase, to infer the properties of these binary systems. In particular, we observe a trend of clustering of flares at some phases as $P_{\rm orb}$ increases, as consistent with a progression from tight, circular or mildly eccentric orbits at short periods, to wider and more eccentric orbits at longer orbital periods. Finally, we estimate the expected number of flares for a given source for our limiting flux and provide the recipe for calculating them for the limiting flux of future hard X-ray observatories. (Abridged).Comment: Accepted for publication in Astronomy and Astrophysics. 23 pages, 8 figures. Full catalog files will be available at CDS and at http://www.ifc.inaf.it/sfxt/ Fixed typos and updated reference